## A Hint on Learning Physics

You cannot learn physics

justby memorizing formulas - you must also learn their meanings! (Of course, you may also have to memorize a few formulas, but there is an easier way to do this.)Every equation is a summary of an

idea. Each symbol in an equation represents something. The equation itself expresses arelationshipbetween these things. You have to know the meaning of every symbol and the relationships expressed by the equation, and then you will know theidea. To learn physics you must know theidea.Just picking out an equation from a list, or from memory, and then plugging in values, is not enough. You have to know what it all means. Compare this to balancing your checkbook: You may know how to add and subtract, but the arithmetic is only a tool for getting the final answer (your account balance). You also have to know which items are deposits and which items represent checks, (this is like knowing the meaning of the symbols in an equation), and you have to know that you

adddeposits andsubtractchecks (this is analogous to knowing the relationship between the symbols).This may sound like extra work, but it actually can make your job easier. Once you know the

ideaexpressed by an equation it is easier to remember that equation, and easier to know what to do with it.Try to think of it this way:

Put the Principle first -- the equation comes last.